1. Field of the Invention
The present invention relates to vehicle suspension systems. More specifically, the invention relates to a semi-independent suspension design that can be used in either a front- or rear-suspension application in either a two- or four-wheel drive vehicle.
2. Related Art
A variety of suspension systems are available for cars, trucks and other wheeled vehicles. The particular suspension design selected depends on a number of considerations. These considerations include the purpose of the vehicle, the gross vehicle weight, whether the suspension is for the front or the rear of the vehicle, whether the wheels are steerable, whether the wheels are driven, et cetera. No suspension is ideal for all applications.
For heavy-duty applications, a conventional beam axle design provides strength, rigidity, accurate steering and tire-wear control. The beam axle, however, provides poor articulation (suspension flex; jounce and rebound). Independent wheel suspensions tend to provide better articulation. However, independent suspensions tend to provide less accurate steering and have greater tire-wear, smaller load-carrying capacity and lower rigidity. Examples of independent wheel suspensions include the MacPherson suspension, the twin I-beam suspensions disclosed in U.S. Pat. No. 3,948,337 to Richardson et al. and United Kingdom Patent Application 2,038,734 of Kishline, and short-long-arm (SLA) suspensions.
Due to its strength and rigidity, the beam-axle suspension is used for heavy-duty applications. When articulation is of primary concern, independent suspensions are used. What is needed is a suspension which combines the strength and rigidity of the beam axle with the articulation of an independent suspension.